In general, a rigid substrate is used as a substrate of a thin film laminate of semiconductor thin films, but a flexible substrate such as a plastic film may be used in some cases for the purpose of improving productivity or reducing the cost because of the lightness and the easiness of handling attributed to the use of roll. Patent Literature 1 discloses a thin film laminated body manufacturing apparatus that conveys intermittently at a predetermined pitch a band-shaped flexible substrate (polyimide film) supplied from an unwinding roll, laminates a plurality of different thin films having different properties on the flexible substrate using a plurality of film forming units arranged in the conveying direction of the flexible substrate, and winds the substrate on a product roll.
In such the thin film laminated body manufacturing apparatus, there are known a type in which a film is formed while conveyed in a lateral position, that is, positioned from a width direction of a band-shaped flexible substrate to a horizontal direction, and a type in which a film is formed while conveyed in a longitudinal position, that is, positioned from a width direction of the band-shaped flexible substrate to a vertical direction. The latter type has benefits in that the installation area is small and the surface of the substrate is not easily contaminated compared to the former type. However, when the conveying span is lengthened, it is difficult to maintain the conveying height to be constant against the gravity, and there is a noticeable tendency that wrinkles occur on the surface of the flexible substrate or the flexible substrate is drooped.
Therefore, as shown in FIGS. 1A and 1B, the inventors have contrived a device adjusting a conveying height of a flexible substrate 1 in a manner such that a pair of upper sandwiching rollers 30 and a pair of lower sandwiching rollers 30′ are disposed between film forming units 20 and 20 constituting a thin film laminated body manufacturing apparatus so as to respectively sandwich the upper and lower edges of the flexible substrate 1, and an upward lifting force and a downward pulling force are applied to the upper and lower edges of the flexible substrate 1 so that the rotation directions of the sandwiching portions of respective sandwiching rollers have the inclination angles +θ and −θ directed obliquely upward and downward with respect to the conveying direction F of the flexible substrate 1 (refer to Patent Literatures 1 to 3).